Our invention relates to an apparatus for data transfer with disklike record media, and more specifically to an apparatus for the recording and/or reproduction of coded data with use of interchangeable flexible magnetic disks, now commonly referred to as floppy disks, that are used in protective envelopes or jackets to make up disk cartridges. Still more specifically, our invention deals with such a data transfer apparatus of the class having a pair of magnetic heads for data transducing contact with the opposite faces of the magnetic disk.
Flexible magnetic disks may be described as being either single or double sided depending upon whether one or both of its opposite faces are used for data storage. A data transfer apparatus for use with double sided disks or disk cartridges has a pair of magnetic transducer heads. The first of these heads is substantially fixed in a direction normal to the plane of the magnetic disk. The second transducer head is typically mounted on a pivotal head arm for movement therewith into and out of data transfer contact with the magnetic disk. A solenoid is a known example of actuator for such pivotal motion of the head arm. An advantage of this prior art construction is that the head arm can be readily solenoid actuated to move the second transducer head away the magnetic disk for the travel of both heads in its radial direction for track to track accessing, thereby avoiding damage or wear of the disk due to friction that would otherwise be caused by sliding engagement of the disk with both transducer heads. Offsetting this advantage, however, are the longer access time and the higher cost of the apparatus because of the use of the solenoid.
These weaknesses are absent from the data transfer apparatus described and claimed in Japanese Laid Open Patent Application No. 58-77080 filed by Teac Corporation and laid open to public inspection on May 10, 1983. This prior art devices teaches to interlock the second transducer head with the disk clamp mechanism and hence to dispense with the solenoid. The second transducer head is sprung into data transfer contact with the magnetic disk as the clamp mechanism is hand actuated to clamp the disk against the drive hub assembly following the loading of the disk cartridge into the apparatus.
This solution has proved unsatisfactory, however. The user may inadvertently actuate the clamp mechanism when no disk cartridge is loaded in the apparatus. Then the second transducer head, mounted on the pivotal head arm, will be spring energized into direct contact with the first head. Since the opposed faces of both transducer heads have a smooth, mirrorlike finish to offer a minimum friction to the magnetic disk, they will stick together upon direct contact with each other, so firmly that they may not easily come apart. Such direct contact of the transducer heads under spring pressure may also result in the destruction of their gimbal supports.
An obvious remedy for this problem might be to provide some means for inhibiting the operation of the clamp mechanism, even if it is activated manually, when no disk cartridge is loaded in the apparatus. The pair of transducer heads will then not make direct contact with each other. However, such inhibiting means would be overloaded and ruined if the user inadvertently activated the clamp mechanism without previously loading a disk cartridge in the apparatus. The inhibiting means might of course be made rugged enough to withstand such excessive loading but then would add to the cost of the data transfer apparatus. The provision of the inhibiting means is further objectionable as such means make difficult the readjustment or repair of the clamp mechanism, the later being unactuable unless the disk cartridge is loaded.